A Son’s Deafness Prompts a Scientific Journey

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Lydia Denworth and her son Alex at home in Brooklyn. His deafness was not discovered until relatively late, age 2.CreditCreditMichael Nagle for The New York Times

By Katherine Bouton

April 14, 2014

Like almost all newborns in this country, Alex Justh was given a hearing test at birth. He failed, but his parents were told not to worry: He was a month premature and there was mucus in his ears. A month later, an otoacoustic emission test, which measures the response of hair cells in the inner ear, came back normal.

Alex was the third son of Lydia Denworth and Mark Justh (pronounced Just), and at first they “reveled at what a sweet and peaceful baby he was,” Ms. Denworth writes in her new book, “I Can Hear You Whisper: An Intimate Journey Through the Science of Sound and Language,” being published this week by Dutton.

But Alex began missing developmental milestones. He was slow to sit up, slow to stand, slow to walk. His mother felt a “vague uneasiness” at every delay. He seemed not to respond to questions, the kind one asks a baby: “Can you show me the cow?” she’d ask, reading “Goodnight, Moon.” Nothing. No response.

At 18 months Alex unequivocally failed a hearing test, but there was still fluid in his ears, so the doctor recommended a second test. It wasn’t until 2005, when Alex was 2 ½, that they finally realized he had moderate to profound hearing loss in both ears.

This is very late to detect deafness in a child; the ideal time is before the first birthday. Alex’s parents took him to Dr. Simon Parisier, an otolaryngologist at New York Eye and Ear Infirmary, who recommended a cochlear implant as soon as possible.

“Age 3 marked a critical juncture in the development of language,” Ms. Denworth writes. “I began to truly understand that we were not just talking about Alex’s ears. We were talking about his brain.”

Today Alex is an active 11-year-old who, like his older brothers, is a student at Berkeley Carroll, a private school in Brooklyn. He plays basketball, baseball — whatever sport is in season. With the implant and a hearing aid, his hearing is within the normal range. He scores 100 percent on a speech recognition test, though this does not mean he hears the way hearing children do.

Ms. Denworth, 47, is a science writer by profession, and her book explores both what happened to her own child and the relationship between the brain and sound and language.

She and I met one chilly March day at her Park Slope brownstone, a fire in the living room radiating warmth. (Like Alex, I use a cochlear implant and a hearing aid, as I relate in my own book, “Shouting Won’t Help: Why I — and 50 Million Other Americans — Can’t Hear You.”)

Alex’s hearing loss is a result of a rare congenital condition called Mondini dysplasia, in which the cochlea fails to form completely. It is often accompanied by a second condition, enlarged vestibular aqueduct syndrome. Because the vestibular system also controls balance, Mondini and the syndrome probably contributed to Alex’s delayed gross motor skills.

Marc Marschark, a professor at the National Technical Institute for the Deaf in Rochester, says that no matter whether deaf children were born to deaf parents who use sign language, or whether they have implants and hearing aids, “the one constant is that they are all still deaf.”

Dr. Marschark hypothesizes that deaf children use their brains differently from hearing children. They quickly learn to pay attention to the visual world, and that leads to differences in brain structure. “Deaf children are not hearing children who can’t hear,” he said. “There are subtle cognitive differences between the two groups.”

David B. Pisoni, a cognitive neuroscientist at the Indiana University School of Medicine, has been studying children with cochlear implants for 22 years. (The first F.D.A. clinical trials on pediatric cochlear implants were done at this center.) He is interested in cognitive processing — learning and memory, attention, language comprehension and production — in deaf children. For children with cochlear implants, success in these areas is highly variable, he said, stressing the “highly.”

This variability in cognitive success affects academic achievement. Although some deaf children do very well academically, an alarming number do not. The median reading level by age 18 in deaf children “has not changed in 40 years,” as Dr. Marschark put it. It remains stuck at fourth-grade level.

Studies have found that deaf children from families who identify themselves as culturally deaf, and use American Sign Language, are generally on a par with hearing children in terms of reading, because they have been exposed to language since birth. But 95 percent of deaf children are born to hearing parents. Those children have no exposure to language until they get a cochlear implant or are entered into an American Sign Language program. Early exposure to language is crucial to learning to read. Those studies of 18-year-olds may yield very different results when children who were implanted at 6 months or a year reach that age.

There are difficulties. For the 5 percent born to deaf parents, learning to read is complicated by the lack of a written form of sign language. Written English is essentially a different language.

Children with hearing aids or cochlear implants, on the other hand, speak the same language they are learning to read, and can benefit from phonics. But cochlear implant surgery cannot be done earlier than 6 to 8 months, so deaf children have no exposure to language during that time. And the devices are imperfect, leading to further hurdles to understanding language.

Alex received his implant relatively late, but he benefited from having some residual hearing, and he has grown up in a language-rich environment, two factors that predict success in reading. As Anne Fernald at Stanford has shown, the more a child is talked to, the better he will read.

“Whatever Alex missed by the delay,” Ms. Denworth told me, “he’s made it up. It’s partly that he’s lucky. Would he be in better shape if he’d had more sound earlier? Maybe.”

Or maybe not. Dr. Marschark and Peter C. Hauser ask rhetorically in the book “Deaf Cognition”: “Are there any deaf children for whom language is not an issue?” From my own experience, I would ask if there are any deaf adults for whom language is not an issue.

Alex came home from school as Ms. Denworth and I were finishing up. He sat down to talk with us for a few minutes. He seemed a little shy, and he had a very quiet voice — so quiet that I couldn’t hear it and his mother had to repeat some of what he said. But what he said was uncannily similar to my experiences as a deaf adult.

I asked him what bothered him most about hearing loss. “When someone says, ‘Never mind,’ ” he replied, without hesitation. I laughed. For me, I said, it’s “Never mind, it’s not important.”

Does he read lips? He wasn’t sure, but he said he could hear better when he was looking at someone. I asked if his friends made a special effort when they talked to him. “The kids in my class are kind of loud,” he said. Loudness does not equal intelligibility.

Asked if he liked the country, where his family has a large working farm, he replied, “The country is easier on my ears.” And he loves the beach. “Sitting on the beach late at night when there’s nobody there,” he said. “It’s noisy but I like to hear the waves.”

Alex’s experience shows what many implant users know. “The cochlear implant itself is not the magic bullet,” his mother said. “It just gives you access to sound, and then you have to work at it.”

Alex is working at it, and it seems clear he will do fine.

Correction:

An article on Tuesday about the author Lydia Denworth and her son Alex Justh, who is deaf and uses a cochlear implant and a hearing aid, paraphrased incorrectly from a comment by Marc Marschark, a professor at the National Technical Institute for the Deaf in Rochester. Dr. Marschark said deaf children have differences that can affect learning. He did not say that “all deaf children have some cognitive challenges.”

A version of this article appears in print on , on Page D5 of the New York edition with the headline: A Son’s Deafness Prompts a Scientific Journey. Order Reprints | Today’s Paper | Subscribe